Fuel supply apparatus

Abstract

A movable portion is movable from a closed position, in which the movable portion is in contact with a valve element, to an opened position so as to supply fuel from a fuel portion to a compression chamber through a fuel passage. A drive control unit supplies of a small driving current, which is sufficient to maintain the movable portion at the closed position, to a coil portion so as to move the movable portion from the opened position to the closed position. The drive control unit switches the supply of the small driving current to supply of the large driving current in the course of the movement of the movable portion to the closed position by supplying the small driving current.

1. A fuel supply apparatus for a vehicle, the fuel supply apparatus comprising:
 a fuel portion for receiving fuel; 
 a valve element located in a fuel passage, which communicates with the fuel portion; 
 a delivery portion for supplying fuel pressurized in a compression chamber, which is located downstream of the fuel passage; 
 a movable portion movable between a closed position and an opened position and configured to make contact with the valve element; 
 a coil portion for applying magnetic attractive force to the movable portion; 
 a drive circuit portion configured to manipulate the movable portion from the opened position to the closed position by supplying a first driving current to the coil portion; the drive circuit portion being configured to maintain the movable portion at the closed position by supplying a second driving current, which is less than the first driving current, to the coil portion; 
 drive control means for controlling the drive circuit portion by switching supply of the second driving current to supply of the first driving current to move the movable portion to the closed position in the course of movement of the movable portion to the closed position by supplying the second driving current; and 
 fuel-pressure detection means for detecting pressure of fuel supplied from the delivery portion, 
 wherein the drive control means is configured to determine a start point, at which supply of the second driving current is started, based on the pressure of fuel, and 
 wherein the drive control means is configured to perform a learning processing to gradually increase a switch period, which is from the start point to a switch point at which supply of the second driving current is switched to supply of the first driving current. 
 
     
     
       2. The fuel supply apparatus according to  claim 1 , wherein the drive control means is configured to perform the learning processing and set the switch period based on change in the start point. 
     
     
       3. The fuel supply apparatus according to  claim 1 , wherein the drive control means is configured to perform the learning processing and set the switch period based on change in the pressure of fuel. 
     
     
       4. The fuel supply apparatus according to  claim 1 , further comprising:
 oscillation detecting means for detecting oscillation, 
 wherein the drive control means is configured to perform the learning processing and set the switch period based on change in the oscillation. 
 
     
     
       5. The fuel supply apparatus according to  claim 1 , wherein the drive control means is configured to perform the learning processing and set the switch period in each of a plurality of operation range segments, which are defined based on an operation state of the vehicle. 
     
     
       6. The fuel supply apparatus according to  claim 5 ,
 wherein the plurality of operation range segments includes a first segment and a second segment, 
 the drive control means is configured to perform the learning processing and set the switch period in the first segment, and 
 the drive control means is configured to apply the switch period, which is set in the first segment, to the second segment, in which the switch period is estimated to be greater than the switch period in the first segment, without the learning processing. 
 
     
     
       7. The fuel supply apparatus according to  claim 1 , wherein the drive control means performs the learning processing on condition of continuation of a steady state in which an operation state of the vehicle is steadily maintained. 
     
     
       8. The fuel supply apparatus according to  claim 1 , wherein the drive control means terminates the learning processing when an operation state of the vehicle is out of the steady state in the course of the learning processing. 
     
     
       9. The fuel supply apparatus according to  claim 1 , wherein the drive control means is configured to set the switch period at zero as an initial value in advance of performing the learning processing. 
     
     
       10. A fuel supply apparatus for a vehicle, the fuel supply apparatus comprising:
 a fuel portion for receiving fuel; 
 a valve element located in a fuel passage, which communicates with the fuel portion; 
 a delivery portion for supplying fuel pressurized in a compression chamber, which is located downstream of the fuel passage; 
 a movable portion movable between a closed position and an opened position and configured to make contact with the valve element; 
 a coil portion for applying magnetic attractive force to the movable portion; 
 a drive circuit portion configured to supply an electric current to the coil portion at a drive voltage; 
 drive control means for controlling a start point at which the drive circuit portion supplies the electric current; 
 voltage control means for setting a pre-close drive voltage at a position close to the closed position when the movable portion is moved to the closed position, based on the start point and controlling the drive voltage at the pre-close drive voltage; and 
 fuel-pressure detection means for detecting pressure of fuel supplied from the delivery portion, 
 wherein the drive control means is configured to determine the start point based on the pressure of fuel, and 
 wherein the voltage control means is configured to perform a learning processing to gradually decrease the pre-close drive voltage. 
 
     
     
       11. The fuel supply apparatus according to  claim 10 , wherein the voltage control means is configured to perform the learning processing and set the pre-close drive voltage based on change in the start point. 
     
     
       12. The fuel supply apparatus according to  claim 10 , wherein the voltage control means is configured to perform the learning processing and set the pre-close drive voltage based on change in the pressure of fuel. 
     
     
       13. The fuel supply apparatus according to  claim 10 , further comprising:
 oscillation detecting means for detecting oscillation, 
 wherein the voltage control means is configured to perform the learning processing and set the pre-close drive voltage based on change in the oscillation. 
 
     
     
       14. The fuel supply apparatus according to  claim 10 , wherein the voltage control means is configured to perform the learning processing and set the pre-close drive voltage in each of a plurality of operation range segments, which are defined based on an operation state of the vehicle. 
     
     
       15. The fuel supply apparatus according to  claim 14 ,
 wherein the plurality of operation range segments includes a first segment and a second segment, 
 the voltage control means is configured to perform the learning processing and set the pre-close drive voltage in the first segment, and 
 the voltage control means is configured to apply the pre-close drive voltage, which is set in the first segment, to the second segment, in which the pre-close drive voltage is estimated to be greater than the pre-close drive voltage in the first segment, without the learning processing. 
 
     
     
       16. The fuel supply apparatus according to  claim 10 , wherein the voltage control means performs the learning processing on condition of continuation of a steady state in which an operation state of the vehicle is steadily maintained. 
     
     
       17. The fuel supply apparatus according to  claim 10 , wherein the voltage control means terminates the learning processing when an operation state of the vehicle is out of the steady state in the course of the learning processing. 
     
     
       18. The fuel supply apparatus according to  claim 10 , wherein the voltage control means is configured to set a maximum drive voltage as an initial value in advance of performing the learning processing. 
     
     
       19. A method for controlling a fuel supply apparatus for a vehicle, the method comprising:
 supplying a small driving current to a coil portion so as to apply magnetic force to attract a movable portion and thereby to manipulate a valve element from an opened position, in which the movable portion is in contact with the valve element to supply fuel into a compression chamber, to a closed position, in which the valve element is seated to a seat body, the small driving current being sufficient to maintain the movable portion at the closed position; 
 switching supply of the small driving current to supply of a large driving current, which is larger than the small driving current in the course of movement of the movable portion to the closed position by the supplying of the small driving current; 
 detecting pressure of fuel supplied from the delivery portion; 
 determining a start point, at which supply of the second driving current is started, based on the pressure of fuel; and 
 performing a learning processing to gradually increase a switch period, which is from the start point to a switch point at which supply of the second driving current is switched to supply of the first driving current. 
 
     
     
       20. A method for controlling a fuel supply apparatus for a vehicle, the method comprising:
 supplying an electric current to a coil portion so as to apply magnetic force to attract a movable portion and thereby to manipulate a valve element from an opened position, in which the movable portion is in contact with the valve element to supply fuel into a compression chamber, to a closed position, in which the valve element is seated to a seat body, at a drive voltage; 
 controlling a start point of the supplying of the electric current; 
 setting a pre-close drive voltage at a position close to the closed position when the movable portion is moved to the closed position, based on the start point; 
 controlling the drive voltage at a pre-close drive voltage; 
 detecting pressure of fuel supplied from the delivery portion; 
 determining the start point based on the pressure of fuel; and 
 performing a learning processing to gradually decrease the pre-close drive voltage.